| Abstract: | Adsorption isotherms have been obtained for two direct dyes on unmercerised cotton and viscose yarns at the boil in the presence of sodium chloride. Both dyes, CI Direct Red 81 and CI Direct Green 26, show evidence of monomolecular layer adsorption. Controlled acid hydrolysis of cotton was carried out in order to remove non-crystalline cellulose, and dye sorption values were obtained for the residues. Accessible surface areas have been calculated from the saturation values obtained from the reciprocal plots of the adsorption data. The results are interpreted in terms of a crystalline fibril model of the cotton fibre. |
